MSP430ISelDAGToDAG.cpp revision 7a969d8c47d8916099ff7a2dcb87cf42137e03c4
1//===-- MSP430ISelDAGToDAG.cpp - A dag to dag inst selector for MSP430 ----===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines an instruction selector for the MSP430 target. 11// 12//===----------------------------------------------------------------------===// 13 14#include "MSP430.h" 15#include "MSP430ISelLowering.h" 16#include "MSP430TargetMachine.h" 17#include "llvm/DerivedTypes.h" 18#include "llvm/Function.h" 19#include "llvm/Intrinsics.h" 20#include "llvm/CallingConv.h" 21#include "llvm/Constants.h" 22#include "llvm/CodeGen/MachineFrameInfo.h" 23#include "llvm/CodeGen/MachineFunction.h" 24#include "llvm/CodeGen/MachineInstrBuilder.h" 25#include "llvm/CodeGen/MachineRegisterInfo.h" 26#include "llvm/CodeGen/SelectionDAG.h" 27#include "llvm/CodeGen/SelectionDAGISel.h" 28#include "llvm/Target/TargetLowering.h" 29#include "llvm/Support/Compiler.h" 30#include "llvm/Support/Debug.h" 31using namespace llvm; 32 33/// MSP430DAGToDAGISel - MSP430 specific code to select MSP430 machine 34/// instructions for SelectionDAG operations. 35/// 36namespace { 37 class MSP430DAGToDAGISel : public SelectionDAGISel { 38 MSP430TargetLowering &Lowering; 39 const MSP430Subtarget &Subtarget; 40 41 public: 42 MSP430DAGToDAGISel(MSP430TargetMachine &TM, CodeGenOpt::Level OptLevel) 43 : SelectionDAGISel(TM, OptLevel), 44 Lowering(*TM.getTargetLowering()), 45 Subtarget(*TM.getSubtargetImpl()) { } 46 47 virtual void InstructionSelect(); 48 49 virtual const char *getPassName() const { 50 return "MSP430 DAG->DAG Pattern Instruction Selection"; 51 } 52 53 // Include the pieces autogenerated from the target description. 54 #include "MSP430GenDAGISel.inc" 55 56 private: 57 SDNode *Select(SDValue Op); 58 bool SelectAddr(SDValue Op, SDValue Addr, SDValue &Base, SDValue &Disp); 59 60 #ifndef NDEBUG 61 unsigned Indent; 62 #endif 63 }; 64} // end anonymous namespace 65 66/// createMSP430ISelDag - This pass converts a legalized DAG into a 67/// MSP430-specific DAG, ready for instruction scheduling. 68/// 69FunctionPass *llvm::createMSP430ISelDag(MSP430TargetMachine &TM, 70 CodeGenOpt::Level OptLevel) { 71 return new MSP430DAGToDAGISel(TM, OptLevel); 72} 73 74// FIXME: This is pretty dummy routine and needs to be rewritten in the future. 75bool MSP430DAGToDAGISel::SelectAddr(SDValue Op, SDValue Addr, 76 SDValue &Base, SDValue &Disp) { 77 // Try to match frame address first. 78 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) { 79 Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i16); 80 Disp = CurDAG->getTargetConstant(0, MVT::i16); 81 return true; 82 } 83 84 switch (Addr.getOpcode()) { 85 case ISD::ADD: 86 // Operand is a result from ADD with constant operand which fits into i16. 87 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) { 88 uint64_t CVal = CN->getZExtValue(); 89 // Offset should fit into 16 bits. 90 if (((CVal << 48) >> 48) == CVal) { 91 SDValue N0 = Addr.getOperand(0); 92 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(N0)) 93 Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i16); 94 else 95 Base = N0; 96 97 Disp = CurDAG->getTargetConstant(CVal, MVT::i16); 98 return true; 99 } 100 } 101 break; 102 case MSP430ISD::Wrapper: 103 SDValue N0 = Addr.getOperand(0); 104 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) { 105 Base = CurDAG->getTargetGlobalAddress(G->getGlobal(), 106 MVT::i16, G->getOffset()); 107 Disp = CurDAG->getTargetConstant(0, MVT::i16); 108 return true; 109 } else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(N0)) { 110 Base = CurDAG->getTargetExternalSymbol(E->getSymbol(), MVT::i16); 111 Disp = CurDAG->getTargetConstant(0, MVT::i16); 112 } 113 break; 114 }; 115 116 Base = Addr; 117 Disp = CurDAG->getTargetConstant(0, MVT::i16); 118 119 return true; 120} 121 122 123 124/// InstructionSelect - This callback is invoked by 125/// SelectionDAGISel when it has created a SelectionDAG for us to codegen. 126void MSP430DAGToDAGISel::InstructionSelect() { 127 DEBUG(BB->dump()); 128 129 // Codegen the basic block. 130#ifndef NDEBUG 131 DOUT << "===== Instruction selection begins:\n"; 132 Indent = 0; 133#endif 134 SelectRoot(*CurDAG); 135#ifndef NDEBUG 136 DOUT << "===== Instruction selection ends:\n"; 137#endif 138 139 CurDAG->RemoveDeadNodes(); 140} 141 142SDNode *MSP430DAGToDAGISel::Select(SDValue Op) { 143 SDNode *Node = Op.getNode(); 144 DebugLoc dl = Op.getDebugLoc(); 145 146 // Dump information about the Node being selected 147 #ifndef NDEBUG 148 DOUT << std::string(Indent, ' ') << "Selecting: "; 149 DEBUG(Node->dump(CurDAG)); 150 DOUT << "\n"; 151 Indent += 2; 152 #endif 153 154 // If we have a custom node, we already have selected! 155 if (Node->isMachineOpcode()) { 156 #ifndef NDEBUG 157 DOUT << std::string(Indent-2, ' ') << "== "; 158 DEBUG(Node->dump(CurDAG)); 159 DOUT << "\n"; 160 Indent -= 2; 161 #endif 162 return NULL; 163 } 164 165 // Few custom selection stuff. 166 switch (Node->getOpcode()) { 167 default: break; 168 case ISD::FrameIndex: { 169 assert(Op.getValueType() == MVT::i16); 170 int FI = cast<FrameIndexSDNode>(Node)->getIndex(); 171 SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16); 172 if (Node->hasOneUse()) 173 return CurDAG->SelectNodeTo(Node, MSP430::ADD16ri, MVT::i16, 174 TFI, CurDAG->getTargetConstant(0, MVT::i16)); 175 return CurDAG->getTargetNode(MSP430::ADD16ri, dl, MVT::i16, 176 TFI, CurDAG->getTargetConstant(0, MVT::i16)); 177 } 178 } 179 180 // Select the default instruction 181 SDNode *ResNode = SelectCode(Op); 182 183 #ifndef NDEBUG 184 DOUT << std::string(Indent-2, ' ') << "=> "; 185 if (ResNode == NULL || ResNode == Op.getNode()) 186 DEBUG(Op.getNode()->dump(CurDAG)); 187 else 188 DEBUG(ResNode->dump(CurDAG)); 189 DOUT << "\n"; 190 Indent -= 2; 191 #endif 192 193 return ResNode; 194} 195